The invention relates to a video signal processing arrangement for television signals encoded in digital form comprising means for compressing and/or expanding the size of the television picture represented by the video signal and means for rotating the television picture represented by the video signal.
The invention further relates to a video signal processing arrangement for television signals encoded in digital form comprising first and second video signal inputs, a video signal output, first means for compressing and/or expanding the size of a television picture represented by the first video signal, second means for compressing and/or expanding the size of a television picture represented by the second video signal, means for combining the outputs of the first and second compressing and/or expanding means, and means for rotating the television picture represented by a video signal.
Television video effects generators normally provide facilities for compressing (squeezing) and expanding (zooming) the television picture represented by a video signal derived from a picture source (television camera, video tape recorder, etc). Such generators may also include means for rotating the television picture either about an axis normal to the picture or an axis in the plane of the picture. Further, the generator may be a multichannel arrangement with the output of each channel fed to a mixing circuit so that two or more video signals may be compresed or expanded independently and allocated to desired portions of the final picture.
It has been found that when the rotator is connected at the channel input and the rotated picture is subsequently squeezed, part of the picture may be lost at the corners. An arrangement has been used in which the compressing and/or expanding means is combined with the rotating means in a single unit. However this produces a complex arrangement which is expensive and comparatively complicated to operate when certain effects are desired. Also, in a multichannel device a single channel has to be reserved for rotational effects, as the combined unit is too expensive to provide in each channel. Further, if two or more video signals are mixed the mixed signal cannot be rotated unless a further rotator is provided.